Physics P1 and P2: Discussi0n

[beststriker]

charges were opposite on both sphere but their magnitude (size) was equal. this is the correct statement.

 

[UxaiR]

nd y is an airplane earthed while refuelling

to prevent any spark which may cause fire .!

 

[beststriker]

nd y is an airplane earthed while refuelling

the charge is accumulated to a very large amount, so it will produce a spark which which will result in fire, so aeroplane should be earthed.
this what i wrote.........

 

[Aizen]

i wrote da same but wasnt sure abt it

 

[beststriker]

please discuss last question of section B....

 

[book worm]

it is earthed because during refueling opposite charges may develop in fuel and aeroplane due to friction. this may lead to fire or explosion and therefore to prevent it earthing is done..

 

[jafar]

mcq.
1. when u r flying in the aeroplane, your mass remains same but weight decreases. that what i choose. is it right...??
2. what was the answer to the mcq that states about the lightning and sound of thunder being heard 6 sec apart? i choose A.

in last question of section B, what was the resistance in the thermistor ? my answer was 1158 ohm. what was urs........

1) weight decreases mass remains same
2) part A

Part B Q11; last part: 1157.8 ~ 1158ohms



plane is earthed while refuling so to minimise the danger of fire by created charges

 

[Aizen]

nd wat was dat current voltage graph like?was the current increasing or decreasing at first

 

[beststriker]

it was a confusion........
they both are directly proportional when ohm law is applied, but here the temperature was changing, so ohm rule was not applied. so i was confused and made a curve which i thought is wrong.

 

[jafar]

please discuss last question of section B....

Tell da questions....

 

[Aizen]

i know dat it was gonna b constant at end, but cudnt figure out whether current will increase or decrease at first

 

[jafar]

the current wud increase at first with the voltage and at the will becum constant....
nott sure though :s

 

[Aizen]

but wasnt resistance also increasing due to increasing temperature

 

[jafar]

ohms law vont be applied in dis situation

 

[Aizen]

but isnt current always inverserly proportional to resistance even if no ohms law

 

[jafar]

nd directly propotional to voltage

 

[OakMoon!]

Firstly people let me clear your confusion about the Q of principal conversion of energy. KINETIC ENERGY=1/2 mv2..... sahi baat? there is no acceleration involved in gain of kinetic energy and so only velocity needed... Wether the velocity was constant or not there will be an increase in the kinetic energy according to the equation.. and he was falling so potential energy was being changed to kinetic energy... they had asked about the PRINCIPLE conversion, though heat is also produced but principally it was PE to KE... hope this clears.
And secondly the sec B last Q had a curve, current not necessarily becomes constant but there is a turn.. see the buk... u ll find a curve for a filament lamp.

 

[Micky]

nd y is an airplane earthed while refuelling

I think since this is kinda a repeatish question writing that the +ive and -ive charger attract each other would gain the first mark and that this would cause a spark that would ignite the fuel would be the second mark.

 

[jafar]

i dnt agree wid u hamid cuz when there is no acceleration KE will be constant which means that PE is not converted into KE nd is only converted into Thermal energy cuz of friction....

nd yea u r rite bout da curve....

 

[beststriker]

Is cutting was allowed in p2 or it would be penalised?
Diagrams were to be drawn with pencil.